In a 2022 review of mast cell disorders, Leru [60] notes that mast cells “contain a plethora of active mediators, such as biogenic amines (histamine, serotonin), serines and other proteases (tryptase, serine S1, chymase, cathepsin G, granzyme, carboxypeptidase), lysosomal enzymes, and proteoglycans (heparin, chondroitin sulfates).” So far, the roles of mast cell proteases tryptase, chymase, and carboxypeptidase A3 in COVID-19 pathogenesis have been described. The gene discussed is CMA1; the disease is COVID-19.